JP2009059748A - Coil device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coil device of a new structure including a ring shaped core 1, an insulating layer 3 for covering a surface of the core, and a coil 2 wound around the core 1 through the insulating layer 3, capable of reducing a size of the coil device while maintaining an inductance value. <P>SOLUTION: The insulating layer 3 for covering the surface of the core 1 of the coil device comprises an outer circumference wall 70 for covering an outer circumferential surface 7 of the core 1, and an upper surface wall 73 and a lower surface wall 74 for covering an upper surface 71 and a lower surface 72 of the core 1. An inner circumferential surface 75 of the core 1 is exposed from the insulating layer 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a coil device provided in a rectifier circuit, a noise prevention circuit, a resonance circuit and the like in various AC devices.

As shown in FIG. 8, the conventional coil device is formed by winding a coil (5) around a C-shaped core (4) having a magnetic gap part (40). A pair of lead portions (50) and (51) are formed (Patent Document 1). As shown in FIG. 9, the core (4) is covered with an insulating layer (6) made of synthetic resin. As shown in FIG. 10, the coil (5) is formed by winding a conducting wire (52) a predetermined number of times around the core (4). In the coil device, the insulating layer (6) provides electrical insulation between the core (4) and the coil (5). The conducting wire (52) is covered with an insulating resin for the main purpose of preventing mutual short circuit in the state of being wound around the core (4).
JP 2002-74748 A

In recent years, the AC device equipped with the coil device as described above has been downsized, and accordingly, further downsizing of the coil device is required.
Further, it may be necessary to further increase the inductance of the coil device, and even in such a case, it is necessary to prevent an increase in the size of the coil device.

  By the way, the inductance L of the coil device is determined by using the number of turns N of the coil, the magnetic path length l, the cross-sectional area orthogonal to the magnetic path of the core (hereinafter, simply referred to as the cross-sectional area of the core) A, The following equation 1 can be used.

(Equation 1)
L = (A / l) × μ × N ²

As is clear from Equation 1, the relationship between the inductance L, the cross-sectional area A of the core, the magnetic path length l, and the number of turns N of the coil is proportional to the inductance L and the cross-sectional area A of the core. L and the square of the number of turns N of the coil are in a proportional relationship, and the inductance L and the magnetic path length l are in an inversely proportional relationship.
Therefore, as one method for reducing the size of the coil device while maintaining the inductance at the same value, the core is reduced in size while maintaining the similarity of the cross-sectional shape of the core, and the cross-sectional area A of the core is reduced. A method of increasing the number of turns N of the coil is conceivable. However, in this method, as the core is downsized, the inner diameter of the core central hole also decreases, so the number of conductive wires that can be packed in the core central hole decreases, and the number of turns N of the coil increases. It is difficult. For this reason, there existed a problem which had a limit in size reduction of a coil apparatus.
In order to increase the inductance of the coil device without increasing the size of the coil device, the number of turns N of the coil may be increased without changing the cross-sectional shape of the core. However, since the number of conductive wires that can be packed in the core central hole is limited, it is difficult to increase the number of turns N of the coil indefinitely. was there.

  An object of the present invention is to provide a coil device having a novel structure capable of reducing the size while maintaining the inductance at the same value or increasing the inductance without causing an increase in size.

  Therefore, the present inventors have focused on an insulating layer covering the inner peripheral surface of the core of the coil device, and found that the insulation between the coil and the core can be maintained even if the insulating layer is omitted. We succeeded in miniaturizing the device.

  The coil device according to the present invention includes a ring-shaped core (1), an insulating layer (3) covering the surface of the core (1), and the insulating layer (3) around the core (1). An insulating layer (3) including a coil (2) wound and covering the surface of the core (1) includes an outer peripheral wall (70) covering an outer peripheral surface (7) of the core (1), and a core (1 ), And an inner peripheral surface (75) of the core (1) is exposed from the insulating layer (3). ing.

In the coil device, there is no insulating layer covering the inner peripheral surface (75) of the core (1), and a gap (13) is formed between the inner peripheral surface (75) of the core (1) and the coil (2). Is formed. Due to the presence of the gap (13), the electrical insulation between the core (1) and the coil (2) is maintained even if there is no insulating layer covering the inner peripheral surface (75) of the core (1). .
The reason why the gap (13) as described above is formed is as follows. Since the conducting wire of the coil (2) is made of metal and has elasticity, in the process of winding the conducting wire around the core (1), the conducting wire is formed of the core (1) covered with the insulating layer (3). It does not bend at a right angle at the corner, but bends with a certain radius of curvature. As a result, the lead wire contacts the corner of the core (1) covered with the insulating layer (3), but is separated from the inner peripheral surface (75) of the core (1), and the inside of the core (1). A gap (13) is formed between the peripheral surface (75) and the coil (2).

  In a specific configuration, the core (1) is composed of a ring-shaped magnetic body (14), and the magnetic body (14) is exposed on the surface of the core (1).

  In another specific configuration, the core (1) is a dust core configured by covering the surface of a ring-shaped magnetic body (15) with a powder coating film (30).

  In a more specific configuration, the ring-shaped magnetic body is formed with a magnetic gap portion (10) penetrating in a direction intersecting the central axis of the magnetic body.

  According to the specific configuration, in the assembly process of the coil device, a part of the air-core coil (2) is passed from the magnetic gap part (10) of the core (1) to the central hole (16) of the core, An air-core coil (2) can be mounted around (1).

  Furthermore, in a specific configuration, the coil (2) is configured by winding a conducting wire (22) around the core (1), and at least an inner peripheral surface of the core (1) has a plurality of coil layers. Is formed.

  In the specific configuration, the number of turns of the coil (2) is increased by forming a plurality of coil layers on the inner peripheral surface of the core (1).

  In the coil device according to the present invention, since there is no insulating layer covering the inner peripheral surface (75) of the core (1), the core central hole is enlarged by an area where the insulating layer is closed. Therefore, the conductive wire of the coil (2) can be packed in a region that is larger by the increase in area, thereby increasing the number of turns of the coil (2). Therefore, it is possible to reduce the size of the coil device while maintaining the inductance of the coil device at the same value, or it is possible to increase the inductance without increasing the size.

  Embodiments of the present invention will be specifically described below with reference to the drawings.

  As shown in FIG. 1, the coil device according to the present invention is formed by winding a coil (2) around a C-shaped core (1) having a magnetic gap portion (10) having a width G, and the coil (2). Both end portions form a pair of lead portions (20) and (21).

As shown in FIG. 3, the core (1) is composed of a ring-shaped magnetic body (14), and the magnetic body (14) is exposed on the surface of the core (1). As shown in FIG. 6, the magnetic body (14) is formed with a magnetic gap portion (10) penetrating in a direction intersecting the central axis of the magnetic body (14).
As shown in FIG. 7, the coil (2) is formed by winding a conducting wire (22) around the core (1), and a plurality of coil layers are formed on the inner peripheral surface of the core (1). Yes.

  As shown in FIG. 3, the insulating layer (3) covering the surface of the core (1) includes an outer peripheral wall (70) covering the outer peripheral surface (7) of the core (1), an upper surface (71) of the core (1), and The upper surface wall (73) covering the lower surface (72) and the lower surface wall (74) are formed, and there is no insulating layer covering the inner peripheral surface (75) of the core (1).

Since the conducting wire of the coil (2) is made of metal and has elasticity, in the process of winding the conducting wire around the core (1), the conducting wire is placed on the orthogonal surface of the core (1) at the corner of the core (1). It does not bend at a right angle along, but bends at a certain radius of curvature or more. As a result, the conducting wire comes into contact with the insulating layer (3) only at both ends of the upper surface wall (73) and the lower surface wall (74) covering the upper surface (71) and the lower surface (72) of the core (1). A gap (13) is formed between the inner peripheral surface (75) of the core (1) and the coil (2).
Due to the presence of the gap (13), electrical insulation between the core (1) and the coil (2) is maintained.

  In the manufacturing process of the coil device according to the present invention, as shown in FIG. 4A, first, an air-core coil (22) is produced using a winding jig (not shown). Thereafter, in the air-core coil mounting step, the air-core coil (22) is mounted on the separately manufactured core (1) as shown in FIGS. 4 (a) and 4 (b). First, as shown in FIG. 4 (a), one core end surface (12) far from the center of the core end surface (11) (12) sandwiching the gap (10) of the core (1) is an air core. The air core coil (22) is pushed into the gap (10) of the core (1) as shown by the arrow in the figure so as to enter the central hole (16) of the coil (22). When the air-core coil (22) is further pushed to the back of the core (1), the air-core coil (22) is attached to the core (1) as shown in FIG. 4 (b).

  Also in the manufacturing process, in the process of producing the air core coil (22) using the winding jig, the lead wire is in a state of being curved with a certain radius of curvature or more at the corner portion of the winding jig. Even after the coil (22) is attached to the core (1), the coil (2) remains on the upper surface wall (73) and the lower surface wall (74) covering the upper surface (71) and the lower surface (72) of the core (1). The insulating layer (3) is in contact only at both ends, and a gap (13) is formed between the inner peripheral surface (75) of the core (1) and the coil (2).

  In another coil device according to the present invention, the core (1) is composed of a dust core in which the surface of a magnetic body (15) made of a sintered body is covered with a powder coating film (30) as shown in FIG. Yes. As a material for the powder coating film (30), a CF coating material, an epoxy resin, or the like can be used.

  Also in the coil device, in the process of winding the conducting wire around the core (1), the conducting wire is curved at a corner radius of the core (1) with a certain radius of curvature or more, so the inner peripheral surface of the core (1) and the coil ( A gap (13) is formed between 2).

  As shown in FIG. 8, the conventional coil device is formed by winding a coil (5) around a C-shaped core (4) having a magnetic gap part (40) having a width G, and both ends of the coil (5). The part forms a pair of lead parts (50) (51). The core (4) is covered with an insulating layer (6) made of synthetic resin. As shown in FIG. 9, the insulating layer (6) is an inner peripheral wall of the inner peripheral surface (8) of the core (4). (80) is also covered.

As shown in FIG. 9, when the diameter of the core center hole of the conventional coil device (41) and W _2, area of the core center hole (41) of the coil system, represented by 0.25πW _{² 2.}

As shown in FIG. 6, when the diameter of the core center hole of the coil device of the present invention (16) and W _1, the area of the core center hole (16) of the coil system, represented by 0.25πW ₁ ^2.

The diameter W ₁ of the central hole of the core (1) of the coil device according to the present invention (16), the diameter W ₂ of the central hole of the core (4) of the conventional coil device (41), the core (4) Using the thickness t of the inner peripheral wall (80) of the insulating layer (6) covering the inner peripheral surface (8), it can be expressed by the following equation (2).

(Equation 2)
W ₁ = W ₂ + 2t

  Therefore, the area S of the central hole (16) of the core (1) of the coil device according to the present invention can be expressed by the following equation (3).

(Equation 3)
S = 0.25πW ₁ ² = 0.25 ° (W ₂ + 2t) ²

Comparing the area S of the core central hole (16) of the coil device according to the present invention with the area of the core central hole (41) of the conventional coil device, the area of the core central hole (16) of the coil device according to the present invention S will be larger by π (W ₂ t + t ² ).
Therefore, according to the coil device of the present invention, the number of turns can be increased by packing the coil conductor in a region wide by an area of π (W ₂ t + t ² ).

As is apparent from Equation 1, according to the coil device of the present invention, by increasing the number of turns N of the coil, it is possible to reduce the cross-sectional area A of the core while maintaining the inductance at the same value. There is a reduction in the size of the coil device.
Alternatively, the inductance can be increased without increasing the size of the coil device.

It is a perspective view of a coil device concerning the present invention. It is a partially broken perspective view of the coil device concerning the present invention. It is sectional drawing which shows the principal part of the coil apparatus which concerns on this invention. It is a figure which shows the manufacturing process of the coil apparatus which concerns on this invention. It is sectional drawing which shows the principal part of the other coil apparatus which concerns on this invention. It is sectional drawing of the core of the coil apparatus which concerns on this invention. It is sectional drawing which shows the state by which the several coil layer was formed in the core center hole in the coil apparatus which concerns on this invention. It is a perspective view of the conventional coil apparatus. It is sectional drawing of the core of the conventional coil apparatus. It is sectional drawing which shows the state in which the several coil layer was formed in the core center hole in the conventional coil apparatus.

Explanation of symbols

(1) Core
(10) Magnetic gap
(13) Clearance
(14) Magnetic material
(15) Magnetic material
(2) Coil
(22) Conductor
(3) Insulating layer
(30) Powder coating film
(4) Core
(40) Magnetic gap
(5) Coil
(52) Conductor
(6) Insulating layer

Claims (5)

  A ring-shaped core (1), an insulating layer (3) covering the surface of the core (1), and a coil (2) wound around the core (1) via the insulating layer (3) The insulating layer (3) covering the surface of the core (1) includes an outer peripheral wall (70) covering the outer peripheral surface (7) of the core (1), and an upper surface of the core (1) ( 71) and an upper surface wall (73) and a lower surface wall (74) covering the lower surface (72), and the inner peripheral surface (75) of the core (1) is exposed from the insulating layer (3). Coil device characterized.   The coil device according to claim 1, wherein the core (1) includes a ring-shaped magnetic body (14), and the magnetic body (14) is exposed on a surface of the core (1).   The coil device according to claim 1, wherein the core (1) is a dust core configured by covering a surface of a ring-shaped magnetic body (15) with a powder coating film (30).   The coil device according to claim 2 or 3, wherein the ring-shaped magnetic body is formed with a magnetic gap portion (10) penetrating in a direction intersecting with a central axis of the magnetic body.   The coil (2) is configured by winding a conducting wire (22) around the core (1), and a plurality of coil layers are formed at least on the inner peripheral surface of the core (1). The coil apparatus in any one of thru | or 4.

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